This invention relates to the generation of electrical energy by piezoelectric elements in response to surface waves on a body of water, and particularly to electrical power generating systems comprising a float on the surface of the water and piezoelectric elements suspended from the float.
Electrical power generating systems of the type with which the present invention has utility are shown in U.S. Pat. No. 4,685,296 issued to J. R. Burns. As disclosed in the patent, the subject matter of which is incorporated herein by reference, piezoelectric elements are suspended from a float on a surface of a body of water, particularly an ocean, and the lower ends of the piezoelectric elements are firmly anchored to the ocean floor. The vertical dimensions of the system are established such that at mean water level the piezoelectric elements are stretched a preselected amount, but within the elastic limits of the elements.
As the float moves vertically up and down in response to passing surface waves, the piezoelectric elements are alternately further stretched and relaxed, i.e., alternately strained and destrained. The piezoelectric elements generate electricity in direct proportion to the amount of variable straining of the elements.
Systems of the type disclosed in the patent present many practical problems including difficulties connected with anchoring the system and providing proper tension under changing water depth conditions, tuning the system under changing surface wave conditions, and protecting the system under severe storm conditions. The present invention provides a solution to all these problems.